/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * $Id: hostthre.c,v 1.57 2008-11-06 17:19:57 yangtse Exp $
 ***************************************************************************/

#include "setup.h"


#ifdef NEED_MALLOC_H
#include <malloc.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>     /* required for free() prototypes */
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>     /* for the close() proto */
#endif
#ifdef  VMS
#include <in.h>
#include <inet.h>
#include <stdlib.h>
#endif

#ifdef HAVE_PROCESS_H
#include <process.h>
#endif

#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
#undef in_addr_t
#define in_addr_t unsigned long
#endif

#include "urldata.h"
#include "sendf.h"
#include "hostip.h"
#include "hash.h"
#include "share.h"
#include "strerror.h"
#include "url.h"
#include "multiif.h"
#include "inet_pton.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <api/libcurl/mprintf.h>

#include "inet_ntop.h"

#include "memory.h"
/* The last #include file should be: */
#include "memdebug.h"

#if defined(_MSC_VER) && defined(CURL_NO__BEGINTHREADEX)
#pragma message ("No _beginthreadex() available in this RTL")
#endif

/***********************************************************************
 * Only for Windows threaded name resolves builds
 **********************************************************************/
#ifdef CURLRES_THREADED

/* This function is used to init a threaded resolve */
static bool init_resolve_thread(struct connectdata *conn,
								const char *hostname, int port,
								const struct addrinfo *hints);

#ifdef CURLRES_IPV4
#define THREAD_FUNC  gethostbyname_thread
#define THREAD_NAME "gethostbyname_thread"
#else
#define THREAD_FUNC  getaddrinfo_thread
#define THREAD_NAME "getaddrinfo_thread"
#endif

struct thread_data
{
	HANDLE thread_hnd;
	unsigned thread_id;
	DWORD  thread_status;
	curl_socket_t dummy_sock;   /* dummy for Curl_resolv_fdset() */
	HANDLE mutex_waiting;  /* marks that we are still waiting for a resolve */
	HANDLE event_resolved; /* marks that the thread obtained the information */
	HANDLE event_thread_started; /* marks that the thread has initialized and
                                  started */
	HANDLE mutex_terminate; /* serializes access to flag_terminate */
	HANDLE event_terminate; /* flag for thread to terminate instead of calling
                             callbacks */
#ifdef CURLRES_IPV6
	struct addrinfo hints;
#endif
};

/* Data for synchronization between resolver thread and its parent */
struct thread_sync_data
{
	HANDLE mutex_waiting;   /* thread_data.mutex_waiting duplicate */
	HANDLE mutex_terminate; /* thread_data.mutex_terminate duplicate */
	HANDLE event_terminate; /* thread_data.event_terminate duplicate */
	char * hostname;        /* hostname to resolve, Curl_async.hostname
                             duplicate */
};

/* Destroy resolver thread synchronization data */
static
void destroy_thread_sync_data(struct thread_sync_data * tsd)
{
	if (tsd->hostname)
		free(tsd->hostname);
	if (tsd->event_terminate)
		CloseHandle(tsd->event_terminate);
	if (tsd->mutex_terminate)
		CloseHandle(tsd->mutex_terminate);
	if (tsd->mutex_waiting)
		CloseHandle(tsd->mutex_waiting);
	MEMSET(tsd, 0, sizeof(*tsd));
}

/* Initialize resolver thread synchronization data */
static
BOOL init_thread_sync_data(struct thread_data * td,
						   const char * hostname,
						   struct thread_sync_data * tsd)
{
	HANDLE curr_proc = GetCurrentProcess();

	MEMSET(tsd, 0, sizeof(*tsd));
	if (!DuplicateHandle(curr_proc, td->mutex_waiting,
						 curr_proc, &tsd->mutex_waiting, 0, FALSE,
						 DUPLICATE_SAME_ACCESS))
	{
		/* failed to duplicate the mutex, no point in continuing */
		destroy_thread_sync_data(tsd);
		return FALSE;
	}
	if (!DuplicateHandle(curr_proc, td->mutex_terminate,
						 curr_proc, &tsd->mutex_terminate, 0, FALSE,
						 DUPLICATE_SAME_ACCESS))
	{
		/* failed to duplicate the mutex, no point in continuing */
		destroy_thread_sync_data(tsd);
		return FALSE;
	}
	if (!DuplicateHandle(curr_proc, td->event_terminate,
						 curr_proc, &tsd->event_terminate, 0, FALSE,
						 DUPLICATE_SAME_ACCESS))
	{
		/* failed to duplicate the event, no point in continuing */
		destroy_thread_sync_data(tsd);
		return FALSE;
	}
	/* Copying hostname string because original can be destroyed by parent
	 * thread during gethostbyname execution.
	 */
	tsd->hostname = strdup(hostname);
	if (!tsd->hostname)
	{
		/* Memory allocation failed */
		destroy_thread_sync_data(tsd);
		return FALSE;
	}
	return TRUE;
}

/* acquire resolver thread synchronization */
static
BOOL acquire_thread_sync(struct thread_sync_data * tsd)
{
	/* is the thread initiator still waiting for us ? */
	if (WaitForSingleObject(tsd->mutex_waiting, 0) == WAIT_TIMEOUT)
	{
		/* yes, it is */

		/* Waiting access to event_terminate */
		if (WaitForSingleObject(tsd->mutex_terminate, INFINITE) != WAIT_OBJECT_0)
		{
			/* Something went wrong - now just ignoring */
		}
		else
		{
			if (WaitForSingleObject(tsd->event_terminate, 0) != WAIT_TIMEOUT)
			{
				/* Parent thread signaled us to terminate.
				 * This means that all data in conn->async is now destroyed
				 * and we cannot use it.
				 */
			}
			else
			{
				return TRUE;
			}
		}
	}
	return FALSE;
}

/* release resolver thread synchronization */
static
void release_thread_sync(struct thread_sync_data * tsd)
{
	ReleaseMutex(tsd->mutex_terminate);
}

#if defined(CURLRES_IPV4)
/*
 * gethostbyname_thread() resolves a name, calls the Curl_addrinfo4_callback
 * and then exits.
 *
 * For builds without ARES/ENABLE_IPV6, create a resolver thread and wait on
 * it.
 */
static unsigned __stdcall gethostbyname_thread (void *arg)
{
	struct connectdata *conn = (struct connectdata*) arg;
	struct thread_data *td = (struct thread_data*) conn->async.os_specific;
	struct hostent *he;
	int    rc = 0;

	/* Duplicate the passed mutex and event handles.
	 * This allows us to use it even after the container gets destroyed
	 * due to a resolver timeout.
	 */
	struct thread_sync_data tsd = { 0, 0, 0, NULL };

	if (!init_thread_sync_data(td, conn->async.hostname, &tsd))
	{
		/* thread synchronization data initialization failed */
		return (unsigned) - 1;
	}

	conn->async.status = NO_DATA;  /* pending status */
	SET_SOCKERRNO(conn->async.status);

	/* Signaling that we have initialized all copies of data and handles we
	   need */
	SetEvent(td->event_thread_started);

	he = gethostbyname (tsd.hostname);

	/* is parent thread waiting for us and are we able to access conn members? */
	if (acquire_thread_sync(&tsd))
	{
		/* Mark that we have obtained the information, and that we are calling
		 * back with it. */
		SetEvent(td->event_resolved);
		if (he)
		{
			rc = Curl_addrinfo4_callback(conn, CURL_ASYNC_SUCCESS, he);
		}
		else
		{
			rc = Curl_addrinfo4_callback(conn, SOCKERRNO, NULL);
		}
		release_thread_sync(&tsd);
	}

	/* clean up */
	destroy_thread_sync_data(&tsd);

	return (rc);
	/* An implicit _endthreadex() here */
}

#elif defined(CURLRES_IPV6)

/*
 * getaddrinfo_thread() resolves a name, calls Curl_addrinfo6_callback and then
 * exits.
 *
 * For builds without ARES, but with ENABLE_IPV6, create a resolver thread
 * and wait on it.
 */
static unsigned __stdcall getaddrinfo_thread (void *arg)
{
	struct connectdata *conn = (struct connectdata*) arg;
	struct thread_data *td   = (struct thread_data*) conn->async.os_specific;
	Curl_addrinfo      *res;
	char   service [NI_MAXSERV];
	int    rc;
	struct addrinfo hints = td->hints;

	/* Duplicate the passed mutex handle.
	 * This allows us to use it even after the container gets destroyed
	 * due to a resolver timeout.
	 */
	struct thread_sync_data tsd = { 0, 0, 0, NULL };

	if (!init_thread_sync_data(td, conn->async.hostname, &tsd))
	{
		/* thread synchronization data initialization failed */
		return -1;
	}

	itoa(conn->async.port, service, 10);

	conn->async.status = NO_DATA;  /* pending status */
	SET_SOCKERRNO(conn->async.status);

	/* Signaling that we have initialized all copies of data and handles we
	   need */
	SetEvent(td->event_thread_started);

	rc = Curl_getaddrinfo_ex(tsd.hostname, service, &hints, &res);

	/* is parent thread waiting for us and are we able to access conn members? */
	if (acquire_thread_sync(&tsd))
	{
		/* Mark that we have obtained the information, and that we are calling
		   back with it. */
		SetEvent(td->event_resolved);

		if (rc == 0)
		{
			rc = Curl_addrinfo6_callback(conn, CURL_ASYNC_SUCCESS, res);
		}
		else
		{
			rc = Curl_addrinfo6_callback(conn, SOCKERRNO, NULL);
		}
		release_thread_sync(&tsd);
	}

	/* clean up */
	destroy_thread_sync_data(&tsd);

	return (rc);
	/* An implicit _endthreadex() here */
}
#endif

/*
 * Curl_destroy_thread_data() cleans up async resolver data and thread handle.
 * Complementary of ares_destroy.
 */
void Curl_destroy_thread_data (struct Curl_async *async)
{
	if (async->hostname)
		free(async->hostname);

	if (async->os_specific)
	{
		struct thread_data *td = (struct thread_data*) async->os_specific;
		curl_socket_t sock = td->dummy_sock;

		if (td->mutex_terminate && td->event_terminate)
		{
			/* Signaling resolver thread to terminate */
			if (WaitForSingleObject(td->mutex_terminate, INFINITE) == WAIT_OBJECT_0)
			{
				SetEvent(td->event_terminate);
				ReleaseMutex(td->mutex_terminate);
			}
			else
			{
				/* Something went wrong - just ignoring it */
			}
		}

		if (td->mutex_terminate)
			CloseHandle(td->mutex_terminate);
		if (td->event_terminate)
			CloseHandle(td->event_terminate);
		if (td->event_thread_started)
			CloseHandle(td->event_thread_started);

		if (sock != CURL_SOCKET_BAD)
			sclose(sock);

		/* destroy the synchronization objects */
		if (td->mutex_waiting)
			CloseHandle(td->mutex_waiting);
		td->mutex_waiting = NULL;
		if (td->event_resolved)
			CloseHandle(td->event_resolved);

		if (td->thread_hnd)
			CloseHandle(td->thread_hnd);

		free(async->os_specific);
	}
	async->hostname = NULL;
	async->os_specific = NULL;
}

/*
 * init_resolve_thread() starts a new thread that performs the actual
 * resolve. This function returns before the resolve is done.
 *
 * Returns FALSE in case of failure, otherwise TRUE.
 */
static bool init_resolve_thread (struct connectdata *conn,
								 const char *hostname, int port,
								 const struct addrinfo *hints)
{
	struct thread_data *td = calloc(sizeof(*td), 1);
	HANDLE thread_and_event[2] = {0};

	if (!td)
	{
		SET_ERRNO(ENOMEM);
		return FALSE;
	}

	Curl_safefree(conn->async.hostname);
	conn->async.hostname = strdup(hostname);
	if (!conn->async.hostname)
	{
		free(td);
		SET_ERRNO(ENOMEM);
		return FALSE;
	}

	conn->async.port = port;
	conn->async.done = FALSE;
	conn->async.status = 0;
	conn->async.dns = NULL;
	conn->async.os_specific = (void*) td;
	td->dummy_sock = CURL_SOCKET_BAD;

	/* Create the mutex used to inform the resolver thread that we're
	 * still waiting, and take initial ownership.
	 */
	td->mutex_waiting = CreateMutex(NULL, TRUE, NULL);
	if (td->mutex_waiting == NULL)
	{
		Curl_destroy_thread_data(&conn->async);
		SET_ERRNO(EAGAIN);
		return FALSE;
	}

	/* Create the event that the thread uses to inform us that it's
	 * done resolving. Do not signal it.
	 */
	td->event_resolved = CreateEvent(NULL, TRUE, FALSE, NULL);
	if (td->event_resolved == NULL)
	{
		Curl_destroy_thread_data(&conn->async);
		SET_ERRNO(EAGAIN);
		return FALSE;
	}
	/* Create the mutex used to serialize access to event_terminated
	 * between us and resolver thread.
	 */
	td->mutex_terminate = CreateMutex(NULL, FALSE, NULL);
	if (td->mutex_terminate == NULL)
	{
		Curl_destroy_thread_data(&conn->async);
		SET_ERRNO(EAGAIN);
		return FALSE;
	}
	/* Create the event used to signal thread that it should terminate.
	 */
	td->event_terminate = CreateEvent(NULL, TRUE, FALSE, NULL);
	if (td->event_terminate == NULL)
	{
		Curl_destroy_thread_data(&conn->async);
		SET_ERRNO(EAGAIN);
		return FALSE;
	}
	/* Create the event used by thread to inform it has initialized its own data.
	 */
	td->event_thread_started = CreateEvent(NULL, TRUE, FALSE, NULL);
	if (td->event_thread_started == NULL)
	{
		Curl_destroy_thread_data(&conn->async);
		SET_ERRNO(EAGAIN);
		return FALSE;
	}

#ifdef _WIN32_WCE
	td->thread_hnd = (HANDLE) CreateThread(NULL, 0,
										   (LPTHREAD_START_ROUTINE) THREAD_FUNC,
										   conn, 0, &td->thread_id);
#else
	td->thread_hnd = (HANDLE) _beginthreadex(NULL, 0, THREAD_FUNC,
					 conn, 0, &td->thread_id);
#endif

#ifdef CURLRES_IPV6
	DEBUGASSERT(hints);
	td->hints = *hints;
#else
	(void) hints;
#endif

	if (!td->thread_hnd)
	{
#ifndef _WIN32_WCE
		SET_ERRNO(errno);
#endif
		Curl_destroy_thread_data(&conn->async);
		return FALSE;
	}
	/* Waiting until the thread will initialize its data or it will exit due errors.
	 */
	thread_and_event[0] = td->thread_hnd;
	thread_and_event[1] = td->event_thread_started;
	if (WaitForMultipleObjects(sizeof(thread_and_event) /
							   sizeof(thread_and_event[0]),
							   (const HANDLE*)thread_and_event, FALSE,
							   INFINITE) == WAIT_FAILED)
	{
		/* The resolver thread has been created,
		 * most probably it works now - ignoring this "minor" error
		 */
	}
	/* This socket is only to keep Curl_resolv_fdset() and select() happy;
	 * should never become signalled for read/write since it's unbound but
	 * Windows needs atleast 1 socket in select().
	 */
	td->dummy_sock = socket(AF_INET, SOCK_DGRAM, 0);
	return TRUE;
}


/*
 * Curl_wait_for_resolv() waits for a resolve to finish. This function should
 * be avoided since using this risk getting the multi interface to "hang".
 *
 * If 'entry' is non-NULL, make it point to the resolved dns entry
 *
 * This is the version for resolves-in-a-thread.
 */
CURLcode Curl_wait_for_resolv(struct connectdata *conn,
							  struct Curl_dns_entry **entry)
{
	struct thread_data   *td = (struct thread_data*) conn->async.os_specific;
	struct SessionHandle *data = conn->data;
	long   timeout;
	DWORD  status;
	CURLcode rc;

	DEBUGASSERT(conn && td);

	/* now, see if there's a connect timeout or a regular timeout to
	   use instead of the default one */
	timeout =
		conn->data->set.connecttimeout ? conn->data->set.connecttimeout :
		conn->data->set.timeout ? conn->data->set.timeout :
		CURL_TIMEOUT_RESOLVE * 1000; /* default name resolve timeout */

	/* wait for the thread to resolve the name */
	status = WaitForSingleObject(td->event_resolved, timeout);

	/* mark that we are now done waiting */
	ReleaseMutex(td->mutex_waiting);

	/* close our handle to the mutex, no point in hanging on to it */
	CloseHandle(td->mutex_waiting);
	td->mutex_waiting = NULL;

	/* close the event handle, it's useless now */
	CloseHandle(td->event_resolved);
	td->event_resolved = NULL;

	/* has the resolver thread succeeded in resolving our query ? */
	if (status == WAIT_OBJECT_0)
	{
		/* wait for the thread to exit, it's in the callback sequence */
		if (WaitForSingleObject(td->thread_hnd, 5000) == WAIT_TIMEOUT)
		{
			TerminateThread(td->thread_hnd, 0);
			conn->async.done = TRUE;
			td->thread_status = (DWORD) - 1;
		}
		else
		{
			/* Thread finished before timeout; propagate Winsock error to this
			 * thread.  'conn->async.done = TRUE' is set in
			 * Curl_addrinfo4/6_callback().
			 */
			SET_SOCKERRNO(conn->async.status);
			GetExitCodeThread(td->thread_hnd, &td->thread_status);
		}
	}
	else
	{
		conn->async.done = TRUE;
		td->thread_status = (DWORD) - 1;
	}

	if (entry)
		*entry = conn->async.dns;

	rc = CURLE_OK;

	if (!conn->async.dns)
	{
		/* a name was not resolved */
		if (td->thread_status == CURLE_OUT_OF_MEMORY)
		{
			rc = CURLE_OUT_OF_MEMORY;
			failf(data, "Could not resolve host: %s", curl_easy_strerror(rc));
		}
		else if (conn->async.done)
		{
			if (conn->bits.httpproxy)
			{
				failf(data, "Could not resolve proxy: %s; %s",
					  conn->proxy.dispname, Curl_strerror(conn, conn->async.status));
				rc = CURLE_COULDNT_RESOLVE_PROXY;
			}
			else
			{
				failf(data, "Could not resolve host: %s; %s",
					  conn->host.name, Curl_strerror(conn, conn->async.status));
				rc = CURLE_COULDNT_RESOLVE_HOST;
			}
		}
		else if (td->thread_status == (DWORD) - 1 || conn->async.status == NO_DATA)
		{
			failf(data, "Resolving host timed out: %s", conn->host.name);
			rc = CURLE_OPERATION_TIMEDOUT;
		}
		else
			rc = CURLE_OPERATION_TIMEDOUT;
	}

	Curl_destroy_thread_data(&conn->async);

	if (!conn->async.dns)
		conn->bits.close = TRUE;

	return (rc);
}

/*
 * Curl_is_resolved() is called repeatedly to check if a previous name resolve
 * request has completed. It should also make sure to time-out if the
 * operation seems to take too long.
 */
CURLcode Curl_is_resolved(struct connectdata *conn,
						  struct Curl_dns_entry **entry)
{
	struct SessionHandle *data = conn->data;

	*entry = NULL;

	if (conn->async.done)
	{
		/* we're done */
		Curl_destroy_thread_data(&conn->async);
		if (!conn->async.dns)
		{
			failf(data, "Could not resolve host: %s; %s",
				  conn->host.name, Curl_strerror(conn, conn->async.status));
			return CURLE_COULDNT_RESOLVE_HOST;
		}
		*entry = conn->async.dns;
	}
	return CURLE_OK;
}

int Curl_resolv_getsock(struct connectdata *conn,
						curl_socket_t *socks,
						int numsocks)
{
	const struct thread_data *td =
					(const struct thread_data *) conn->async.os_specific;

	if (td && td->dummy_sock != CURL_SOCKET_BAD)
{
		if (numsocks)
		{
			/* return one socket waiting for writable, even though this is just
			   a dummy */
			socks[0] = td->dummy_sock;
			return GETSOCK_WRITESOCK(0);
		}
	}
	return 0;
}

#ifdef CURLRES_IPV4
/*
 * Curl_getaddrinfo() - for Windows threading without ENABLE_IPV6.
 */
Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
								const char *hostname,
								int port,
								int *waitp)
{
	struct hostent *h = NULL;
	struct SessionHandle *data = conn->data;
	struct in_addr in;

	*waitp = 0; /* don't wait, we act synchronously */

	if (Curl_inet_pton(AF_INET, hostname, &in) > 0)
		/* This is a dotted IP address 123.123.123.123-style */
		return Curl_ip2addr(AF_INET, &in, hostname, port);

	/* fire up a new resolver thread! */
	if (init_resolve_thread(conn, hostname, port, NULL))
	{
		*waitp = TRUE;  /* please wait for the response */
		return NULL;
	}

	/* fall-back to blocking version */
	infof(data, "init_resolve_thread() failed for %s; %s\n",
		  hostname, Curl_strerror(conn, ERRNO));

	h = gethostbyname(hostname);
	if (!h)
	{
		infof(data, "gethostbyname(2) failed for %s:%d; %s\n",
			  hostname, port, Curl_strerror(conn, SOCKERRNO));
		return NULL;
	}
	return Curl_he2ai(h, port);
}
#endif /* CURLRES_IPV4 */

#ifdef CURLRES_IPV6
/*
 * Curl_getaddrinfo() - for Windows threading IPv6 enabled
 */
Curl_addrinfo *Curl_getaddrinfo(struct connectdata *conn,
								const char *hostname,
								int port,
								int *waitp)
{
	struct addrinfo hints;
	Curl_addrinfo *res;
	int error;
	char sbuf[NI_MAXSERV];
	int pf;
	struct SessionHandle *data = conn->data;

	*waitp = FALSE; /* default to synch response */

	/*
	 * Check if a limited name resolve has been requested.
	 */
	switch (data->set.ip_version)
	{
	case CURL_IPRESOLVE_V4:
		pf = PF_INET;
		break;
	case CURL_IPRESOLVE_V6:
		pf = PF_INET6;
		break;
	default:
		pf = PF_UNSPEC;
		break;
	}

	if (pf != PF_INET)
	{
		/* see if we have an IPv6 stack */
		curl_socket_t s = socket(PF_INET6, SOCK_DGRAM, 0);
		if (s == CURL_SOCKET_BAD)
		{
			/* Some non-IPv6 stacks have been found to make very slow name resolves
			 * when PF_UNSPEC is used, so thus we switch to a mere PF_INET lookup if
			 * the stack seems to be a non-ipv6 one. */

			pf = PF_INET;
		}
		else
		{
			/* This seems to be an IPv6-capable stack, use PF_UNSPEC for the widest
			 * possible checks. And close the socket again.
			 */
			sclose(s);
		}
	}

	MEMSET(&hints, 0, sizeof(hints));
	hints.ai_family = pf;
	hints.ai_socktype = conn->socktype;
#if 0 /* removed nov 8 2005 before 7.15.1 */
	hints.ai_flags = AI_CANONNAME;
#endif
	itoa(port, sbuf, 10);

	/* fire up a new resolver thread! */
	if (init_resolve_thread(conn, hostname, port, &hints))
	{
		*waitp = TRUE;  /* please wait for the response */
		return NULL;
	}

	/* fall-back to blocking version */
	infof(data, "init_resolve_thread() failed for %s; %s\n",
		  hostname, Curl_strerror(conn, ERRNO));

	error = Curl_getaddrinfo_ex(hostname, sbuf, &hints, &res);
	if (error)
	{
		infof(data, "getaddrinfo() failed for %s:%d; %s\n",
			  hostname, port, Curl_strerror(conn, SOCKERRNO));
		return NULL;
	}
	return res;
}
#endif /* CURLRES_IPV6 */
#endif /* CURLRES_THREADED */
